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Abstract:

A sheet ejection mechanism including a sheet ejection roller capable of
rotating along a selective direction and having an arc portion and a
plane portion, the arc portion and the plane portion forming a D-shape
cross-section, and a pinch member configured at a position adjacent to
the sheet ejection roller, wherein a recording medium is clamped and
conveyed between the pinch member and the arc portion of the sheet
ejection roller, and a gap is formed between the plane portion and the
pinch member for allowing the recording medium to pass. Also, the present
invention provides a duplex sheet feeding system having the sheet
ejection mechanism.

Claims:

1. A sheet ejection mechanism, comprising:a sheet ejection roller capable
of rotating along a selective direction and having an arc portion and a
plane portion, the arc portion and the plane portion forming a D-shape
cross-section; anda pinch member configured at a position adjacent to the
sheet ejection roller;wherein a recording medium is clamped and conveyed
between the pinch member and the arc portion of the sheet ejection
roller, and a gap is formed between the plane portion and the pinch
member for allowing the recording medium to pass.

2. The sheet ejection mechanism of claim 1, wherein the pinch member is a
driven roller.

3. The sheet ejection mechanism of claim 1, wherein the pinch member is a
plate.

4. The sheet ejection mechanism of claim 3, wherein the plate connects to
an elastic member for driving the plate to recover automatically.

5. The sheet ejection mechanism of claim 3 or 4, wherein the friction
coefficient between the plate and the recording medium is smaller than
the friction coefficient between the arc portion and the recording
medium.

6. The sheet ejection mechanism of claim 1, further comprising a sensor
for detecting the direction of rotation of the sheet ejection roller.

7. A duplex sheet feeding system, comprising:a feed roller for conveying a
recording medium from a feeding path into a scanning zone and being
scanned by a scanning module;a conveying roller for conveying the
recording medium out of the scanning zone and into an ejecting path;a
returning roller for returning the recording medium conveyed out of the
scanning zone back into the scanning zone through a returning path; anda
sheet ejection mechanism where the recording medium entering through the
ejecting path, the sheet ejection mechanism comprising:a sheet ejection
roller capable of rotating along a selective direction and having an arc
portion and a plane portion, the arc portion and the plane portion
forming a D-shape cross-section; anda pinch member configured at a
position adjacent to the sheet ejection roller;wherein the recording
medium is clamped and conveyed outward between the pinch member and the
arc portion when the sheet ejection roller rotates along a main direction
and the recording medium is clamped and conveyed between the pinch member
and the arc portion for being conveyed back into the returning path for
being scanned when the sheet ejection roller rotates along an opposite
direction, and a gap is formed between the plane portion and the pinch
member for allowing the recording medium to pass.

8. The duplex sheet feeding system of claim 7, further comprising a paper
weight configured at the returning path and the ejecting path.

9. The duplex sheet feeding system of claim 8, wherein the paper weight
comprises an arc plate and a spring connecting to the arc plate.

10. The duplex sheet feeding system of claim 7, wherein the length of the
arc portion is larger than the distance between the returning roller and
the gap formed between the sheet ejection roller and the pinch member.

11. The duplex sheet feeding system of claim 7, wherein the length of the
arc portion is larger than the distance between the conveying roller and
the gap formed between the sheet ejection roller and the pinch member.

12. The duplex sheet feeding system of claim 7, wherein the pinch member
is a driven roller.

13. The duplex sheet feeding system of claim 7, wherein the pinch member
is a plate.

14. The duplex sheet feeding system of claim 13, wherein the plate
connects to an elastic member for driving the plate to recover
automatically.

15. The duplex sheet feeding system of claim 13, further comprising a
sensor locating at an entering position of the scanning zone.

16. The duplex sheet feeding system of claim 12 or 13, wherein the
friction coefficient between the plate and the recording medium is
smaller than the friction coefficient between the arc portion and the
recording medium.

17. The duplex sheet feeding system of claim 8, wherein the length of the
arc portion is larger than the distance between the feed roller and a
location where the scanning module locates in the scanning zone.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The invention relates to a sheet ejection mechanism and a sheet
feeding system, and more particularly, to a sheet ejection mechanism in a
duplex sheet feeding system and the duplex sheet feeding system.

[0003]2. Description of the Prior Art

[0004]In general, overlap of feeding edge and trailing edge of a recording
medium occurs in a gap between two sheet ejection rollers. Such overlap
may easily stop and jam the recording medium during conveying and lower
the quality of printing or scanning.

[0005]Please refer to FIG. 1A. The U.S. Pat. No. 6,307,614 B1 discloses a
method for scanning the recording medium. When the recording medium is
scanned with duplex scanning, the feeding edge can not enter the gap
formed between a roller 52 and a roller 54, because of the direction of
rotation of the two rollers 52, 54, and the recording medium is buckled
in front of the gap. Please refer to FIG. 1B. The thrust of the feeding
edge of the recording medium overcomes the friction between the recording
medium and the rollers so that the rollers 52, 54 are driven to rotate
along an opposite direction and convey the recording medium into the gap
between the rollers 52, 54.

[0006]Such type of design, however, causes problem as follow:

[0007]The system reduces its amount of recording medium ejection because
the feeding edge of the recording medium, which has done its second side
imaging, stops for a while before entering the gap between the two
rollers.

[0008]In general, the used surface of the recording medium is not smoothly
and for the recording medium to enter two tightly adjacent rollers,
jamming easily occurs. The recording medium buckles and the quality of
output degrades when the recording medium enters the gap formed between
two rollers 52, 54.

[0009]The upper part of the recording medium and the lower part of the
recording medium feed along opposite direction when the recording medium
enters the gap formed between two rollers 52, 54. Additionally, the upper
part of the recording medium also feeds along opposite direction to the
rotation direction of the sheet ejection roller. The upper part of the
recording medium has therefore been pulled, which increases overall
system torque. The upper part of the recording medium may also be damaged
by the pulling force.

[0010]To solve the problem mentioned above, please refer to FIG. 1C. The
U.S. Pat. No. 6,493,060 B2 discloses a movable driven roller in the sheet
ejection mechanism. The gap is formed between two rollers using high
power solenoid for overcoming the elasticity of the driven roller before
the feeding edge of the recording medium goes to the roller 62 for
scanning. The feeding edge of the recording medium can then pass the
rollers more smoothly. Such mechanism design, however, uses expensive
high power solenoid and needs an additional promotional mechanism for
moving the driven roller.

[0011]Additionally, the surface of the recording medium produces the mark
of the roller engaging by the force of the roller contact. For this
reason, the original recording medium is broken by the mark.

SUMMARY OF THE INVENTION

[0012]The present invention provides a sheet ejection mechanism. The sheet
ejection mechanism includes a sheet ejection roller and a pinch member.
The sheet ejection roller is capable of rotating along a selective
direction and having an arc portion and a plane portion. The arc portion
and the plane portion form a D-shape cross-section. The pinch member is
configured at a position adjacent to the sheet ejection roller. A
recording medium is clamped and conveyed between the pinch member and the
arc portion of the sheet ejection roller, and a gap is formed between the
plane portion and the pinch member for allowing the recording medium to
pass.

[0013]The present invention provides a duplex sheet feeding system. The
duplex sheet feeding system includes a feed roller, a conveying roller, a
returning roller and a sheet ejection mechanism. The sheet ejection
mechanism includes a sheet ejection roller and a pinch member. The feed
roller conveys a recording medium from a feeding path into a scanning
zone and being scanned by a scanning module. The conveying roller conveys
the recording medium out of the scanning zone and into an ejecting path.
The returning roller returns the recording medium conveyed out of the
scanning zone back into the scanning zone through a returning path. The
sheet ejection mechanism is the recording medium entering through the
ejecting path. The sheet ejection mechanism includes a sheet ejection
roller and a pinch member. The sheet ejection roller is capable of
rotating along a selective direction and having an arc portion and a
plane portion. The arc portion and the plane portion form a D-shape
cross-section. The pinch member is configured at a position adjacent to
the sheet ejection roller. The recording medium is clamped and conveyed
outward between the pinch member and the arc portion when the sheet
ejection roller rotates along a main direction. The recording medium is
clamped and conveyed between the pinch member and the arc portion for
being conveyed back into the returning path for being scanned when the
sheet ejection roller rotates along an opposite direction. The gap is
formed between the plane portion and the pinch member for allowing the
recording medium to pass.

[0014]These and other objectives of the present invention will no doubt
become obvious to those of ordinary skill in the art after reading the
following detailed description of the preferred embodiment that is
illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1A˜FIG. 1C are schematic diagrams of the prior art.

[0016]FIG. 2 is a schematic diagram of a first embodiment according to the
present invention.

[0017]FIG. 3A˜FIG. 3c are schematic diagrams of a single sheet
feeding path of the first embodiment according to the present invention.

[0018]FIG. 4A˜FIG. 4F are schematic diagrams of a duplex sheet
feeding path of the first embodiment according to the present invention.

[0019]FIG. 5 is a schematic diagram of a second embodiment according to
the present invention.

[0020]FIG. 6 is a schematic diagram of a third embodiment according to the
present invention.

[0021]FIG. 7 is a schematic diagram of a fourth embodiment according to
the present invention.

DETAILED DESCRIPTION

[0022]Please refer to FIG. 2. FIG. 2 is a schematic diagram of the first
embodiment according to the present invention. A duplex sheet feeding
system 100 disclosed in the embodiment includes a feeding path 1 and an
ejecting path 2. A scanning unit module 105 is configured between the
feeding path 1 and the ejecting path 2. A sheet ejection mechanism 3 is
located at the end of the ejecting path 2. The end of a returning path 4
connects to the sheet ejection mechanism 3, and the other end connects to
the feeding path 1. A pickup roller 101, a separation roller 102, a first
feed roller 103, and a second feed roller 104 locate in the feeding path
1. The scanning unit module 105 is located after the second feed roller
104 in the feeding path 1. A conveying roller 108 is configured in the
ejecting path 2 and is a driven roller. A returning roller 107 is
configured in the returning path 4 and is also a driven roller. An
intermediate roller 106 engages with the conveying roller 108 and the
returning roller 107. The intermediate roller 106 is a driving roller
which engages with the conveying roller 108 for conveying the recording
medium out of the scanning zone. The intermediate roller 106 engages with
the returning roller 107 for returning the recording medium back the
returning path 4 into the feeding path 1 and the scanning zone for
scanning. The intermediate roller 106 can be a single roller or two
independent driving rollers for engaging the conveying roller 108 and the
returning roller 107 respectively. For this and other embodiment,
single-roller form of the intermediate roller 106 reduces the number of
transmission shaft and simplifies the flow paths of the sheet feeding
system.

[0023]A sheet ejection roller 109 is configured in the end of the ejecting
path 2 and is a driving roller. A pinch member 110 engages with the sheet
ejection roller 109 and is also a sheet ejection driven roller of the
present invention. The sheet ejection roller 109 has an arc portion A and
a plane portion B, which form a D-shape cross-section. A sensor 111 is
configured between the second feed roller 104 and the scanning unit
module 105. Additionally, the sheet ejection roller 109 is controlled by
a low power motor or an actuator, and its rotation can be detected by a
sensor. The technology of the low power motor or the simple brake has
been obvious to a person having ordinary skill, and it is omitted herein
for brevity.

[0024]Please refer to FIG. 3A. A pickup roller 101 picks the recording
medium P from an input tray (not shown) and the feeding roller 102
conveys the recording medium P. The recording medium P is conveyed by the
first feed roller 103 and the second feed roller 104 through the scanning
zone for generating the picture by the scanning unit module 105. The
recording medium P is clamped in the gap formed between the intermediate
roller 106 and the conveying roller 108 and then conveyed into between
the sheet ejection roller 109 and the pinch member 110, where the gap
formed between therein (the plane portion B of the sheet ejection roller
109 and the pinch member 110) allows the feeding edge of the recording
medium P to pass and not be stopped.

[0025]Please refer to FIG. 3B. The sheet ejection roller 109 begins to
rotate counterclockwise after a predetermined time set by the system when
the end of the recording medium P leaves the sensor 111. The arc portion
A of the sheet ejection roller 109 contacts the recording medium P and
forms a clipping gap with the pinch member 110 for conveying the
recording medium P before the trailing edge of the recording medium P
leaves the gap formed by the intermediate roller 106 and the conveying
roller 108. For the following description, rotation of any roller along
counterclockwise direction is recognized as forward rotation in the
present invention.

[0026]The length of the arc portion of the sheet ejection roller 109 is
larger than the distance between the gap D formed between the conveying
roller 108 and the intermediate roller 106 and the gap E formed between
the sheet ejection roller 109 and the pinch member 110 such that
conveying the recording medium P between the sheet ejection roller 109
and the pinch member 110 can be smooth.

[0027]Please refer to FIG. 3c. The recording medium P is ejected to the
output tray by the sheet ejection roller 109 and the pinch member 110.

[0028]Please refer to FIG. 4A. The pickup roller 101 picks the recording
medium P from the input tray (not shown), and the feeding roller 102
conveys the recording medium P picked by the pickup roller 101. The
recording medium P is fed by the first feed roller 103 and the second
feed roller 104 and then passed through the scanning zone for the
scanning unit module 105 to generate the picture on it. The recording
medium P is clamped by the gap formed between the intermediate roller 106
and the conveying roller 108, and the recording medium P is conveyed
between the sheet ejection roller 109 and the pinch member 110. Since the
gap is formed between the plane B of the D-shape sheet ejection roller
109 and the pinch member 110, the feeding edge of the recording medium P
encounters no resistance when the recording medium P passes through the
gap between the sheet ejection roller 109 and the pinch member 110.

[0029]Please refer to FIG. 4B. The sheet ejection roller 109 begins to
rotate counterclockwise after a predetermined time set by the system when
the end of the recording medium P leaves the sensor 111. The arc portion
A of the sheet ejection roller 109 contacts the recording medium P and
forms a clipping gap with the pinch member 110 for conveying the
recording medium P before the trailing edge of the recording medium P
leaves the gap formed by the intermediate roller 106 and the conveying
roller 108. For the following description, rotation of any roller along
counterclockwise direction is recognized as forward rotation in the
present invention.

[0030]The length of the arc portion A of the sheet ejection roller 109 is
larger than the distance between the gap D formed between the conveying
roller 108 and the intermediate roller 106 and the gap E formed between
the sheet ejection roller 109 and the pinch member 110 such that
conveying the recording medium P between the sheet ejection roller 109
and the pinch member 110 can be smooth.

[0031]Please refer to FIG. 4c. The sheet ejection roller 109 begins to
rotate clockwise before the railing edge of the recording medium P leaves
the sheet ejection roller 109 and the pinch member 110 after the
predetermined time set by the system. The original trailing edge of the
recording medium P turns into feeding edge of the recording medium P and
goes along the second feeding path for forming picture on the second
side.

[0032]The length of the arc portion A of the sheet ejection roller 109 is
larger than the distance between the gap C formed between the returning
roller 107 and the intermediate roller 106 and the gap E formed between
the sheet ejection roller 109 and the pinch member 110 such that
conveying the recording medium P from the sheet ejection roller 109 and
the pinch member 110 to the gap C formed between the returning roller 107
and the intermediate roller 106 can be smooth.

[0033]Please refer to FIG. 4D. The feeding edge of the recording medium P
is clamped and conveyed by the gap formed between the intermediate roller
106 and the returning roller 107 at the same time the sheet ejection
roller 109 keeps to rotate clockwise for returning the recording medium P
back with the pinch member 110. The sheet ejection roller 109 stops
rotating once the plane B of the sheet ejection roller 109 and the pinch
member 110 form the gap.

[0034]Please refer to FIG. 4E. The recording medium P is clamped and fed
in the gap formed between the intermediate roller 106 and the returning
roller 107 along the returning path 4 and then clamped and fed in the gap
formed between the first feed roller 103 and the second feed roller 104.
The feeding edge of the recording medium P passes through the scanning
unit module 105 via the gap formed between the intermediate roller 106
and the conveying roller 108 and goes into the gap formed between the
sheet ejection roller 109 and the pinch member 110. The recording medium
P overlaps in the group of the sheet ejection rollers (The group of the
sheet ejection roller includes the sheet ejection roller 109 and the
pinch member 110.) if longer recording medium P is used. In such
condition, the recording medium P will not buckle because the gap is
formed between the group of the sheet ejection rollers of the present
invention.

[0035]Please refer to FIG. 4F. The trailing edge of the recording medium P
leaves the sensor 111 after the feeding edge of the recording medium P
enters into the output tray (not shown). The sheet ejection roller 109
begins to rotate counterclockwise after the predetermined time set by the
system. The arc portion A of the sheet ejection roller 109 contacts with
the recording medium P and then forms the gap with the driven roller 110
before the trailing edge of the recording medium P leaves the gap formed
between two feed rollers 104. The recording medium P is conveyed to the
output tray through the gap formed between the sheet ejection roller 109
and the driven roller 110. The recording medium P is finally ejected and
overlapped to the output tray.

[0036]It should be noted again that when the intermediate roller 106 is
replaced with two independent driving rollers, the length of the arc
portion A of the sheet ejection roller 109 is larger than the distance
between the gap formed between the returning roller 107 and the driving
roller that engages with the returning roller 107 and the gap E formed
between the sheet ejection roller 109 and the pinch member 110. The
length of the arc portion A of the sheet ejection roller 109 is also
larger than the distance between the gap formed between the conveying
roller 108 and the driving roller that engages with the conveying roller
108 and the gap E formed between the sheet ejection roller 109 and the
pinch member 110.

[0037]Please refer to FIG. 5. FIG. 5 is a schematic diagram of the second
embodiment according to the present invention. The second embodiment and
the first embodiment use substantially the same way to convey the
recording medium P except that the sheet ejection roller 109 engages with
a plate 113 in the second embodiment. The friction coefficient between
the plate 113 and the recording medium P is smaller than that between the
arc portion A of the sheet ejection roller 109 and the recording medium P
so that conveying the recording medium P is attainable.

[0038]Please refer to FIG. 6. FIG. 6 is a schematic diagram of the third
embodiment according to the present invention. The third embodiment and
the first embodiment use substantially the same way to convey the
recording medium P except that the sheet ejection roller 109 engages with
the plate 113 and contacts with a spring 114 such that the plate 113 can
recover to its height position automatically by elasticity of the spring
114. The friction coefficient between the plate 113 and the recording
medium P is smaller than that between the arc portion A of the sheet
ejection roller 109 and the recording medium P so that conveying the
recording medium P is attainable.

[0039]It should be noted again that the recording media P is conveyed by
the sheet ejection roller 109 in the second and the third embodiments.

[0040]Please refer to FIG. 7. FIG. 7 is a schematic diagram of the fourth
embodiment according to the present invention. The fourth embodiment and
the first embodiment use substantially the same way to convey the
recording medium P except that in the fourth embodiment, a first paper
weight 121 replaces the intermediate roller 106 that engages with the
returning roller 107 in the first embodiment, and a second paper weight
122 replaces the intermediate roller 106 that engages with the conveying
roller 108 in the first embodiment. The first paper weight 121 is
configured in the returning path 4 and the second paper weight 122 is
configured in the ejecting path 2. Additionally, the sensor 111 is
installed between the first feed roller 103 and the second feed roller
104. The sensor 111 is located at an entering position of the scanning
unit module 105. The first paper weight 121 includes a first arc plate
125 and a first paper weight spring 127. The first paper weight spring
127 connects with the first arc plate 125 and is installed on the housing
of the sheet ejection system 100. The second paper weight 122 includes a
second arc plate 126 and a second paper weight spring 128. The second
paper weight spring 128 connects with the second arc plate 128 and is
installed on the housing of the sheet ejection system 100 (not shown).

[0041]The second paper weight 122 of the sheet feeding system 100 prevents
that the recording medium P buckles when the recording medium P has done
its first side imaging in the single sheet feeding process. The first
paper weight 121 of the sheet feeding system 100 prevents that the
recording medium P buckles when the recording medium P has done its
second side imaging in the duplex sheet feeding process of the fourth
embodiment.

[0042]When the trailing edge of the recording medium P enters the gap
formed between two second feed rollers 104, the length of the arc portion
A is larger than the distance between the gap F formed between two second
feed rollers 104 and the scanning zone position G corresponding to the
scanning unit module 105. The sheet ejection roller 109 and the pinch
member 110 begin to rotate for clamping and conveying the feeding edge of
the recording medium P.

[0043]The sheet ejection mechanism of the present invention compacts a
duplex sheet feeding system and longer recording medium P is allowed to
use smoothly. The recording medium P is paper, substrate, document or
something for recording.

[0044]Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made while
retaining the teachings of the invention.